Requests 库学习笔记

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爬虫学习路线第一站 - Requests库的使用

概览

实例引入

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# 引入Requests库
import requests
# 发起GET请求
response = requests.get('https://www.baidu.com/')
# 查看响应类型  requests.models.Response
print(type(response))
# 输出状态码
print(response.status_code)
# 输出响应内容类型  text
print(type(response.text))
# 输出响应内容
print(response.text)
# 输出cookies
print(response.cookies)

各种请求方式

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import requests
# 发起POST请求
requests.post('http://httpbin.org/post')
# 发起PUT请求
requests.put('http://httpbin.org/put')
# 发起DELETE请求
requests.delete('http://httpbin.org/delete')
# 发送HEAD请求
requests.head('http://httpbin.org/get')
# 发送OPTION请求
requests.options('http://httpbin.org/get')

请求

基本GET请求

基本写法

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import requests
response = requests.get('http://httpbin.org/get')
print(response.text)

带参数的GET请求

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import requests
response = requests.get('http://httpbin.org/get?name=jyx&age=18')
print(response.text)

带参数的GET请求(2)

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import requests
# 分装GET请求参数
param = {'name':'jyx','age':19}
# 设置GET请求参数(Params)
response = requests.get('http://httpbin.org/get',params=param)
print(response.text)

解析json

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import requests
response = requests.get('http://httpbin.org/get')
# 获取响应内容
print(type(response.text))
# 如果响应内容是json,就将其转为json
print(response.json())
# 输出的是字典类型
print(type(response.json()))

获取二进制数据

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import requests
response = requests.get('http://github.com/favicon.ico')
# str，bytes
print(type(response.text),type(response.content))
# 输出响应的文本内容
print(response.text)
# 输出响应的二进制内容
print(response.content)
# 下载二进制数据到本地
with open('favicon.ico','wb') as f:
  f.write(response.content)
  f.close()

添加headers

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import requests
# 设置User-Agent浏览器信息
headers = {
      "User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36"
}
# 设置请求头信息
response = requests.get('https://www.zhihu.com/explore',headers=headers)
print(response.text)

基本POST请求

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import requests
# 设置传入post表单信息
data= { 'name':'jyx', 'age':18}
# 设置请求头信息
headers = {
      "User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36"
}
# 设置请求头信息和POST请求参数(data)
response = requests.post('http://httpbin.org/post', data=data, headers=headers)
print(response.text)

响应

response属性

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import requests
response = requests.get('http://www.jianshu.com/')
# 获取响应状态码
print(type(response.status_code),response.status_code)
# 获取响应头信息
 print(type(response.headers),response.headers)
# 获取响应头中的cookies
print(type(response.cookies),response.cookies)
# 获取访问的url
 print(type(response.url),response.url)
# 获取访问的历史记录
 print(type(response.history),response.history)

状态码判断

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import requests
response = requests.get('http://www.jianshu.com/404.html')
# 使用request内置的字母判断状态码
if not response.status_code == requests.codes.ok:
    print('404-1')
response = requests.get('http://www.jianshu.com')
# 使用状态码数字判断
if not response.status_code == 200:
    print('404-2')

requests内置的状态字符

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100: ('continue',),
101: ('switching_protocols',),
102: ('processing',),
103: ('checkpoint',),
122: ('uri_too_long', 'request_uri_too_long'),
200: ('ok', 'okay', 'all_ok', 'all_okay', 'all_good', '\\o/', '✓'),
201: ('created',),
202: ('accepted',),
203: ('non_authoritative_info', 'non_authoritative_information'),
204: ('no_content',),
205: ('reset_content', 'reset'),
206: ('partial_content', 'partial'),
207: ('multi_status', 'multiple_status', 'multi_stati', 'multiple_stati'),
208: ('already_reported',),
226: ('im_used',),
# Redirection.
300: ('multiple_choices',),
301: ('moved_permanently', 'moved', '\\'),
302: ('found',),
303: ('see_other', 'other'),
304: ('not_modified',),
305: ('use_proxy',),
306: ('switch_proxy',),
307: ('temporary_redirect', 'temporary_moved', 'temporary'),
308: ('permanent_redirect', 'resume_incomplete', 'resume',), # These 2 to be removed in 3.0
# Client Error.
400: ('bad_request', 'bad'),
401: ('unauthorized',),
402: ('payment_required', 'payment'),
403: ('forbidden',),
404: ('not_found', '-'),
405: ('method_not_allowed', 'not_allowed'),
406: ('not_acceptable',),
407: ('proxy_authentication_required', 'proxy_auth', 'proxy_authentication'),
408: ('request_timeout', 'timeout'),
409: ('conflict',),
410: ('gone',),
411: ('length_required',),
412: ('precondition_failed', 'precondition'),
413: ('request_entity_too_large',),
414: ('request_uri_too_large',),
415: ('unsupported_media_type', 'unsupported_media', 'media_type'),
416: ('requested_range_not_satisfiable', 'requested_range', 'range_not_satisfiable'),
417: ('expectation_failed',),
418: ('im_a_teapot', 'teapot', 'i_am_a_teapot'),
421: ('misdirected_request',),
422: ('unprocessable_entity', 'unprocessable'),
423: ('locked',),
424: ('failed_dependency', 'dependency'),
425: ('unordered_collection', 'unordered'),
426: ('upgrade_required', 'upgrade'),
428: ('precondition_required', 'precondition'),
429: ('too_many_requests', 'too_many'),
431: ('header_fields_too_large', 'fields_too_large'),
444: ('no_response', 'none'),
449: ('retry_with', 'retry'),
450: ('blocked_by_windows_parental_controls', 'parental_controls'),
451: ('unavailable_for_legal_reasons', 'legal_reasons'),
499: ('client_closed_request',),
# Server Error.
500: ('internal_server_error', 'server_error', '/o\\', '✗'),
501: ('not_implemented',),
502: ('bad_gateway',),
503: ('service_unavailable', 'unavailable'),
504: ('gateway_timeout',),
505: ('http_version_not_supported', 'http_version'),
506: ('variant_also_negotiates',),
507: ('insufficient_storage',),
509: ('bandwidth_limit_exceeded', 'bandwidth'),
510: ('not_extended',),
511: ('network_authentication_required', 'network_auth', 'network_authentication'),

高级操作

文件上传

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import requests
files = {'file':open('favicon.ico','rb')}
# 往POST请求头中设置文件(files)
response = requests.post('http://httpbin.org/post',files=files)
print(response.text)

获取cookies

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import requests
response = requests.get('https://www.baidu.com')
print(response.cookies)
for key,value in response.cookies.items():
    print(key,'=====',value)

会话维持

普通请求

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import requests
requests.get('http://httpbin.org/cookies/set/number/12456')
response = requests.get('http://httpbin.org/cookies')
# 本质上是两次不同的请求，session不一致
print(response.text)

会话维持请求

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import requests
# 从Requests中获取session
session = requests.session()
# 使用seesion去请求保证了请求是同一个session
session.get('http://httpbin.org/cookies/set/number/12456')
response = session.get('http://httpbin.org/cookies')
print(response.text)

证书验证

无证书访问

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import requests
response = requests.get('https://www.12306.cn')
# 在请求https时，request会进行证书的验证，如果验证失败则会抛出异常
print(response.status_code)

关闭证书验证

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import requests
# 关闭验证，但是仍然会报出证书警告
response = requests.get('https://www.12306.cn',verify=False)
print(response.status_code)

消除关闭证书验证的警告

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from requests.packages import urllib3
import requests
# 关闭警告
urllib3.disable_warnings()
response = requests.get('https://www.12306.cn',verify=False)
print(response.status_code)

手动设置证书

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import requests
# 设置本地证书
response = requests.get('https://www.12306.cn', cert=('/path/server.crt', '/path/key'))
print(response.status_code)

代理设置

设置普通代理

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import requests
proxies = {
    "http": "http://127.0.0.1:9743",
    "https": "https://127.0.0.1:9743",
}
# 往请求中设置代理(proxies
)
response = requests.get("https://www.taobao.com", proxies=proxies)
print(response.status_code)

设置带有用户名和密码的代理

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mport requests
proxies = {
    "http": "http://user:password@127.0.0.1:9743/",
}
response = requests.get("https://www.taobao.com", proxies=proxies)
print(response.status_code)

设置socks代理

pip3 install ‘requests[socks]

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import requests
proxies = {
    'http': 'socks5://127.0.0.1:9742',
    'https': 'socks5://127.0.0.1:9742'
}
response = requests.get("https://www.taobao.com", proxies=proxies)
print(response.status_code)

超时设置

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import requests
from requests.exceptions import ReadTimeout   
try:
   # 设置必须在500ms内收到响应，不然或抛出ReadTimeout异常
   response = requests.get("http://httpbin.org/get", timeout=0.5)
            print(response.status_code)
except ReadTimeout:
   print('Timeout')

认证设置

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import requests
from requests.auth import HTTPBasicAuth
r = requests.get('http://120.27.34.24:9001', auth=HTTPBasicAuth('user', '123'))
# r = requests.get('http://120.27.34.24:9001', auth=('user', '123'))
print(r.status_code)

异常处理

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import requests
from requests.exceptions import ReadTimeout, ConnectionError, RequestException
try:
   response = requests.get("http://httpbin.org/get", timeout = 0.5)
           print(response.status_code)
except ReadTimeout:
   # 超时异常
   print('Timeout')
except ConnectionError:
   # 连接异常
   print('Connection error')
except RequestException:
   # 请求异常
   print('Error')
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